What is different between "par" and "de"?
I studied passive voice.
But I can't understand this difference.
1: Ce professeur est respecté de toutes les étudiants.
＝The teacher is respected by all students.

2: Il a été écrasé par une voiture.
＝He was run over by a car.

"de" and "par" ＝ by?
What is different between "de" and "par"?

Question

What is different between "par" and "de"?
I studied passive voice. 
But I can't understand this difference.
1: Ce professeur est respecté de toutes les étudiants.
＝The teacher is respected by all students.

2: Il a été écrasé par une voiture.
＝He was run over by a car.

"de" and "par" ＝ by?
What is different between "de" and "par"?

Answer

Well for students you could use par too. Normally

De = from but some old fashon french can use de instead of par when the subject is a human ( high level language or " soutenu")
Par = from what  or by which is the common sens